The Autolite sparkplug thread.

musclemerc

musclemerc

Senior Member
OK, some of you know 4 member's got free Autolite XP104's from Motorking and at his request he wanted us to post our thought's on them. Well I got around to doing the install today along with a few extra parts and here's we go. At first look at the plug itself I thought man the electrode is awfully small, it's literall the thickness of grandma's sewing needles so how much spark could it possibly give over stock right. I checked the gap before the install and they were all within the factory range .052~.056 so that was'nt an issue, I also checked and double checked for crack's on the plug's themselves again no problem. So I get done with the work and go for the crank test and it took anout half the time it normally takes to fire, my idle was so smooth I actually had to turn off every inside acessory to hear the motor run. So I go for a ride and the throttle is definately showing to be more responsive, but the test is when I get to this intersection to cross onto a busy road and there's alot of on comming traffic. I'm thinking this is the perfect time to go WOT and see what she's got, so i'm off and the Merc moves like a bat outta hell, all I could do is grin, it responds like it never has it just kept pulling and pulling. I give these plugs two thumbs up they worked for me and will probably do the same for you. In closing I would like to thank Motorking for introducing me to these plugs and I will definately reuse them in the future. :burnout:
 
I've been using the XP 103's for over three years now with excellent results!
 
I can't remember if they are XP's or not, but I recently used 103's gapped at .32 and rate them the same or better than motorcraft copper's.
 
i have some XP 103's waiting to go in right now. they've been in my trunk since MV7 when i got my tune.... :o just been too busy to get to them
 
Jay sent me the XP103 plugs, which are 1 step colder than stock, since I'm blown.

First observations: They do not come pre-gapped to the tight SC gaps like most iridium plugs, and the box specifically states that they should be gapped to the specs for the application. When gapping them, it is really easy to measure the gap. The positive electrode is about the same as any plug, but the negative electrode has a little platinum nipple on it facing the positive electrode. Standard electrodes can be hard to measure if the negative electrode isn't perfectly perpendicular to the positive electrode. The little tip on the negative electrode should provide better control of where the spark actually occurs since it provides some focusing. There also should be less shrouding of the flame kernel due to the shape of the negative electrode, it is beveled at the tip instead of flat across the surface. One negative I noticed, maybe not that important but most high end plugs these days come with a protective sleeve slipped over the threads to prevent damage to the tip of the plug. I believe NGK uses cardboard while NipponDenso uses plastic. These plugs were just put in the box.

Today I swapped them out, nothing magical just a plug swap using the proper techniques. A little bit of thread lube, torque them to 10 ft-lb. Fired it up and it started right up, idled smooth. Just like before. Drove it in a variety of conditions, car ran fine. No missing or other problems. I didn't take it WOT, can't do that on the street. First impression is that they work as good as the NGK TR6IX plugs I took out. Maybe I can get it on a dyno soon and see if it lost any power, but it doesn't feel any different on the street.
 
I have a Reinhart install Vortech. I change the copper top Motorcraft Plugs every 10K miles. I would love to find a plug that would last longer.. ie. Iridium or Platinum.I worry about thread wear even at 12 PSI torque.Don't wanna strip a head !!!!!Mucho Grande Dollaros. Heck I ain't even Spanish!!!!
 
I'm sold on the XP'z but when I went toa given link I didn't see a price...How much we talking for a complete set?!?!
 
Iridium plugs will only last longer in a N/A applications from what a couple of tuners have told me.

For SC/Turbo/N2O cars you are better off sticking with Copper because you will still need to change out the Iridium plugs about every 10k.
 
Black_Kannin said:
I'm sold on the XP'z but when I went toa given link I didn't see a price...How much we talking for a complete set?!?!
Click to expand...


RockAuto has them right now for $4.66 each with a $2.00 rebate on each limit 16 plugs per order for the rebate.
I just ordered a set for my 2007 F-150 SCREW
 
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